Validation of a pre-endoscopy risk score for predicting the presence of gastric intestinal metaplasia in a U.S. population.

BACKGROUND AND AIMS: Surveillance of gastric intestinal metaplasia (GIM) may lead to early gastric cancer detection. Our purpose was to externally validate a predictive model for endoscopic GIM previously developed in a veteran population in a second U.S. METHODS: We previously developed a pre-endoscopy risk model for detection of GIM using 423 GIM cases and 1796 control subjects from the Houston Veterans Affairs Hospital. The model included sex, age, race/ethnicity, smoking, and Helicobacter pylori infection with an area under the receiver-operating characteristic curve (AUROC) of .73 for GIM and .82 for extensive GIM. We validated this model in a second cohort of patients from 6 Catholic Health Initiative (CHI)-St Luke's hospitals (Houston, Tex, USA) from January to December 2017. Cases were defined as having GIM on any gastric biopsy sample and extensive GIM as involving both the antrum and corpus. We further optimized the model by pooling both cohorts and assessing discrimination using AUROC. RESULTS: The risk model was validated in 215 GIM cases (55 with extensive GIM) and 2469 control subjects. Cases were older than control subjects (59.8 vs 54.7 years) with more nonwhites (59.1% vs 42.0%) and H pylori infections (23.7% vs 10.9%). The model applied to the CHI-St Luke's cohort had an AUROC of .62 (95% confidence interval [CI], .57-.66) for predicting GIM and of .71 (95% CI, .63-.79) for predicting extensive GIM. When the Veterans Affairs and CHI-St Luke's cohorts were pooled, discrimination of both models improved (GIM vs extensive GIM AUROC: .74 vs .82). CONCLUSIONS: A pre-endoscopy risk prediction model was validated and updated using a second U.S. cohort with robust discrimination for endoscopic GIM. This model should be evaluated in other U.S. populations to risk-stratify patients for endoscopic GIM screening.

Ethnicity Is an Important Consideration in Screening for Gastric Intestinal Metaplasia.

BACKGROUND: Gastric intestinal metaplasia (GIM) is a precursor to gastric adenocarcinoma, making it an attractive target for early detection by endoscopy. The aim of this study was to determine the prevalence, risk factors, and associated histologic findings of GIM among patients undergoing endoscopy in a diverse US population. METHODS: We conducted a retrospective, cross-sectional study of patients undergoing elective endoscopy with gastric biopsies at 6 academic and community centers in Houston, Texas. GIM prevalence was estimated with a 95% confidence interval (CI), and patient demographic and clinical characteristics were summarized using mean with standard deviation, or frequency with percentage. Generalized estimating equations (GEE) were used to compare characteristics between those with and without GIM. RESULTS: Our final cohort consisted of 2685 patients, including 216 cases with GIM and 2469 controls. The prevalence of GIM in our cohort was 8.04% (95% CI 7.07%, 9.14%). The mean age of GIM cases was higher than in the control group (59.8 vs 54.7 years, p < 0.0001). The prevalence of GIM in Asians, Hispanic, Black and Non-Hispanic Whites (NHW) was 14.7%, 11.7%, 9.8% and 5.8%, respectively. On multivariable analysis, factors associated with GIM include age (adj. OR 1.32 per 10 year increase, p < 0.0001), habitual smoking (adj. OR 1.68, p < 0.0001), and race (compared to NHW: Asian, adj. OR 2.34, p = 0.010; Hispanic, adj. OR 2.15, p < 0.001; Black, adj. OR 1.61, p < 0.001). CONCLUSION: Asians, Hispanics, and African Americans have higher rates of GIM than NHW. Ethnicity should be an important consideration on determining who to screen for GIM in the US.

Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests.

BACKGROUND AND AIMS: The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients. METHODS: Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist. RESULTS: There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate. CONCLUSIONS: In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics.